1. Field of the Invention
The current invention relates generally to methods for using laterally moving objects and laterally moving backgrounds to create the perception of depth when the laterally moving objects and laterally moving backgrounds are viewed with viewer glasses having colored lens or filters. The filter for the left eye is of a different color than the filter for the right eye. In a first aspect, the current invention relates to methods for using laterally moving objects and laterally moving backgrounds in live scenes to create the perception of depth when the scenes are viewed with viewer glasses having colored lens or filters. In a second aspect, the current invention relates to methods for using laterally moving objects and laterally moving backgrounds in colored imagery to create the perception of depth when the imagery is viewed with viewer glasses having colored lens or filters. In a third aspect, the current invention relates to colored imagery comprising laterally moving objects and laterally moving backgrounds to create the perception of depth when the imagery is viewed with viewer glasses having colored lens or filters. In a fourth aspect, the current invention relates to computer processes for operating a data processor with a visual display to create the perception of visual depth when the visual display is viewed with viewer glasses having colored lens or filters. The data processor generates colored imagery comprising laterally moving objects and laterally moving backgrounds on the visual display to create the perception of depth.
The methods may be used for live scenes such as stage productions, motion picture films, video tapes and other types of media. The imagery can be displayed on movie screens, video displays (television, computer displays, video games, etc.) and other types of devices. The computer processes can be used with computer screen savers, video games, and other types of systems that generate imagery in real time.
2. Prior Art
The prior art includes methods and devices to use laterally moving objects to create the perception of depth in two-dimensional motion picture films and video displays. These methods and devices are based on the Pulfrich Effect. This effect is produced by viewing laterally moving objects which appear brighter to one eye than the other eye. The basic Pulfrich Effect is commonly produced by placing a dark lens or filter over one eye. Objects that move laterally in one direction appear to be farther away from the observer. Conversely, objects that move laterally in the opposite direction appear to be closer to the observer. The basic Pulfrich Effect is a uni-directional motion sensitive depth effect. The relationship between the direction of movement and the perception of depth is dependent upon which eye is covered by the dark lens. When the right eye is covered by the dark lens, objects moving left to right from the observer's perspective appear to be closer. Objects moving right to left appear to be farther away. When the left eye is covered by the dark lens, objects moving left to right appear to be farther away. Objects moving right to left appear to be closer. These methods and devices have been the subject of various patents.
The apparatus used to produce the basic Pulfrich Effect tends to cause an undesirable side effect. The eye covered by the dark lens receives substantially less light than the other eye. This produces the sensation that one eye is dead or not working. This dead eye effect becomes irritating to observers over time.
U.S. Pat. No. 3,445,153 to Marks is based on the basic Pulfrich Effect. Observers wear special lenses. The lens over one eye reduces the light normally received by the cones (photopic vision).
Dudley discloses in U.S. Pat. No. 4,131,342 a method of combining the basic Pulfrich Effect with a chromostereoscopic effect. The chromostereoscopic effect is based on the finding that objects of colors towards the red end of the visual spectrum appear closer than objects of colors towards the blue end of the spectrum. The chromostereoscopic effect is very weak. It also restricts the use of colors in objects and backgrounds. U.S. Pat. No. 4,131,342 teaches that the basic Pulfrich Effect is due to a "differential visual time-lag" whereby the human visual system processes a brighter image faster than a dimmer image. Therefore the position of moving objects appears to be different for the eye receiving the brighter image than for the eye receiving the dimmer image. The position of moving objects appears to be more advanced for the eye receiving the brighter image than for the eye receiving the dimmer image. This eye to eye difference in the perceived position of moving objects apparently produces the visual depth effect.
U.S. Pat. No. 4,705,371 to Beard is also based on the basic Pulfrich Effect. Observers wear another type of special lenses. The lenses are intended to reduce the dead eye effect.
U.S. Pat. No. 4,836,647 to Beard discloses alternative colored filters to product the basic Pulfrich Effect. The colored lenses were designed to reduce the light from television displays more than the light from normal room lighting. The colored lenses were intended to reduce the dead eye effect.
The four methods above (U.S. Pat. Nos. 3,445,153; 4,131,342; 4,705,371; and 4,836,647) are all limited by the unidirectional nature of the motion sensitive depth effect. They are all also somewhat prone to the dead eye effect.
U.S. Pat. No. 5,751,397 to Osgood teaches a means to produce a bi-directional basic Pulfrich like effect. U.S. Pat. No. 5,751,397 uses objects moving laterally against colored stationary backgrounds or surrounds, laterally moving colored objects, and colored viewing glasses. The left lens of the viewing glasses passes from 4 to 20 times as much light of one color (e.g. red) as the right lens. The right lens of the viewing glasses passes from 4 to 20 times as much light of another color (e.g. green). Objects moving laterally against surrounds of the first color, and laterally moving objects of the first color, appear closer to the observer when they move from left to right and farther away from the observer when they move from right to left. Objects moving laterally against surrounds of the second color, and laterally moving objects of the second color, appear closer to the observer when they move from right to left and farther away from the observer when they move from left to right. The methods of U.S. Pat. No. 5,751,397 allow each eye to receive enough light over time to reduce or even totally avoid the dead eye effect.
With viewing lens that pass at most 20 times as much light of a first color as of a second color, the depth effects are weak unless large areas of saturated color are used in the laterally moving objects or in the backgrounds. Thus, in practical applications such as movies or video games, restricting the color selectivity of the viewing lens to those lens that pass from 4 to 20 times as much light of a first color as of a second color requires that large areas of saturated colors be used for the colored laterally moving objects and/or the backgrounds.